Part 20 (1/2)
Q. _How does INHALING AIR RAPIDLY make the body feel WARM?_
A. As the combustion of the blood is _more rapid_, (in consequence of the introduction _of more oxygen from the air_), therefore _the blood is more heated_, and every part of the body is warmer also.
Q. _Why does HARD WORK produce HUNGER?_
A. Because it produces _quicker respiration_; by which means a _larger amount of oxygen is introduced into the lungs_, and the _capillary combustion increased_. Hunger _is the notice_ (given by our body) to remind us, _that our food-fuel must be replenished_.
Q. _Why does SINGING make us HUNGRY?_
A. Singing _increases respiration_; and as _more oxygen_ is introduced into the lungs, _our food-fuel is more rapidly consumed_.
Q. _Why does READING ALOUD make us feel HUNGRY?_
A. Reading aloud _increases respiration_; and as _more oxygen_ is introduced into the lungs, _our food-fuel is more rapidly consumed_.
Q. _Why do we feel MORE HUNGRY in the DAY-TIME than in the NIGHT-TIME?_
A. As we _breathe more slowly during sleep_, therefore, less _oxygen_ is introduced into the lungs _to consume our food-fuel_.
Q. _Why do we need WARMER CLOTHING by NIGHT than by DAY?_
A. 1st--Because the _night is generally colder_ than the day.
2ndly--As our _respiration is slower_, our _animal combustion is slower also_; in consequence of which, _our bodies are more cold_.
Q. _Why do we PERSPIRE when very HOT?_
A. The pores of the body are _like the safety valves of a steam-engine_; when the heat of the body is too great, the combustible gas and grease _flow out in perspiration_, instead of _burning in the blood_.
Q. _Why do persons feel LAZY and averse to exercise, when they are HALF-STARVED or ILL-FED?_
A. _Animal food_ contains great nourishment, and produces a desire for _active occupations_; but when the body is not supplied with strong food, this desire for muscular action _ceases_, and the person grows slothful.
Q. _Why have persons, who follow HARD OUT-OF-DOORS OCCUPATIONS, more APPEt.i.tE than those who are engaged in SEDENTARY pursuits?_
A. Hard bodily labour in the open air _causes much oxygen to be conveyed into the lungs by inspiration_; the combustion of the food is carried on quickly; _animal heat increased_; and need for nutritious food more quickly indicated _by craving hunger_.
Q. _Why have persons who follow SEDENTARY PURSUITS less APPEt.i.tE than ploughmen and masons?_
A. 1st--The air they inhale _is not so pure_, because its oxygen is partly exhausted: and